A conventional image pickup device having a charge coupled device obtains smear signals outputted from an optical black area where pixels are light-shielded, calculates an average value of the smear signals per line by averaging the smear signals for each column of lines and subtracts the average value from image signals outputted from a predetermined pixel of the charge coupled device, to thereby reduce noises such as smears and the like which are included in the image signals outputted from the charge coupled device.
Moreover, the charge coupled device is controlled not to transmit image signals of predetermined lines in its image pickup area and to output a smear signal for allowing the non-transmitted lines to serve as signal lines of a black level, to thereby reduce noises such as smears and the like (see, e.g., Japanese Patent Application Publication No. 2008-177709 and C246CYMBO 680×500 PIXEL IMPACTRON™ COMPLEMENTARY COLOR CCD IMAGE SENSOR SOCS089-MAY 2005 manufactured by TI).
However, in the aforementioned prior art, the smear signals are obtained from the light-shielded optical black area. Accordingly, it is difficult to accurately calculate an average value due to pixel defects which are latently included in the light-shielded optical black area when the outputted smear signals are averaged for each column of lines. Therefore, it becomes difficult to accurately correct smears.
Further, since a portion of the image pickup area becomes a quasi-optical black area, the image pickup area is reduced. Besides, in case that the charge coupled device has many light-shielded optical black areas, this restricts to making the quasi-optical black.